Unexpected and really bad.
cramps
Beating can be a word for severe setback. Blow is another word for severe setback.
severe
Apyphony.
small ;not major or severe
Panic, sudden, alert, are words for emergency.
Another word for sovereign is severe and is used in a pacifistic way. Aplus answer independent.
U can call it depend on country. For example, Sudden Attack North America is SANA and Korean Sudden Attack is KSA
severe, extravagant, strong, extreme
Another word for very strict or harsh is stern.
A word that means to depart suddenly is "plump" or "plumped"
The suffix that means sudden severe bleeding is "-rrhage." An example of a term with this suffix is "hemorrhage," which refers to sudden and severe bleeding.